Paeoniflorin-6＇-O-benzene sulfonate, a novel compound, protects against autoimmune arthritis by modulating inflammation and bone damage

Aim Paeoniflorin （Pae） is the principal bioactive component of total glucosides of peony （TGP）, which has been widely used in therapy for rheumatoid arthritis （RA）. Paeoniflorin-6＇-O-benzene sulfonate （code： CP-25） , a novel compound that is a newly ester derivatives of Pae, was evaluated in rats with adjuvant-induced ar- thritis （AA） to study its potential anti-arthritic activity. Methods AA rats were randomly divided into different groups and then treated with CP-25 （25, 50, 100 mg· kg^-1） and methotrexate （0. 5 mg · kg^-1）, from day 16 to day 32 after immunization. Arthritis severity was evaluated by clinical manifestation and histopathological examina- tion. The cells proliferation was determined by CCK-8 assay. Activities of IL-1β, IL-6, IL-17, IL-10, TGF-β1, TNF-oL, IIANKL and OPG were assessed by ELISA. The subsets of CD4 ＋T cells were assayed by flow cytometry. Results CP-25 treatment effectively reduced clinical severity scores and blinded histopathological scores compared with AA groups. CP-25-treated rats exhibited a decrease in the pro-inflammatory cytokines （IL-1β, IL-6, IL-17, and TNF-α） , coupled with an increase in the anti-inflammatory cytokines IL-10 and TGF-β1 in serum and macro- phages of AA rats. The flow cytometry analyses of CD4 ＋T cells dramatically demonstrated the immunomodulatory effects of CP-25 on abnormal immune dysfunction. Apart from the anti-inflammatory activity, treatment with CP-25 inhibited the fibroblast-like synoviocyte （FLS） activation and function. Furthermore, CP-25 treatment of AA rats restored the balance between RANKL and OPG in favor of its anti-osteoclastic effects. Conclusions Data presen- ted here demonstrated that administration of CP-25 significantly inhibited the progression of rat AA, with reductions both in arthritic inflammation and bone damage. The protective effects of CP-25 in AA highlight an attribute that is potential as an ideal new anti-arthritic agent for the treatment with human RA.

Application of an ultra performance liquid chromatography-tandem mass spectrometry method to the pharmacokinetics study of paeoniflorin-6'-O-benzene sulfonate and its active paeoniflorin metabolite in rat plasma

OBJECTIVE To establish a rapid,simple,precise and sensitive ultra performance liquid chromatography(UPLC) method for determination of paeoniflorin-6'-O-benzene sulfonate(acylated derivative of Pae,CP-25) and its primary metabolite(Pae,M1) in rat plasma,and to investigate the effects of gender,food and disease status on the pharmacokinetics after oral administration in rats.METHODS Plasma samples and calibrators were extracted with methanol after addition of the internal standard solution.After evaporation of the methanol layer,the residue was reconstituted in mobile phase,and a 2 μL of the sample was injected into a Waters ACQUITY UPLC BEH C18(2.1 mm × 50 mm,1.7 μm) column for separation at a flow rate of 0.5 mL·min^(-1) at 40℃.The mobile phase was composed of 0.1% formic acid in water and methanol(68∶32,V/V).RESULTS The developed UPLC-MS/MS method was linear in the concentration range of 2-800 mg·L^(-1).Validation of the method proved that the method′s precision,selectivity and stability were all within the acceptable limits.Pharmacokinetics study showed that CP-25 could have more extensive distribution in females than that in males but no differences in M1.Food intake could also increase the extent of absorption and decrease the rate of clearance of CP-25 and M1 after oral administration in rats.The disease status would decrease the absorption of CP-25 in rats.Comparing single-and multiple-dosing in adjuvant arthritis(AA) model,absorption of CP-25 and M1 was improved with increasing dosage.CONCLUSION The developed UPLC-MS/MS method is sensitive,specific and was successfully applied to the pharmacokinetics of CP-25 and M1 in rats.And a significant gender,food intake and disease status differences for CP-25 and M1 were observed in this study.